Production of articles by solidifying leather pulp



ilm'rnn Srnres PATENT Genres,

JOHN IV. HYATT AND JOHN H. STEVENS, OF NEWARK, NEW JERSEY.

PRODUCTION OF ARTICLES BY SOLIDIFYING LEATHER PULP.

SPECIFICATION forming part of Letters Patent No. 228,463, dated. June 8, 1880.

Application filed March 1, 1880.

To all whom it may concern:

Be it known that we, JOHN W. HYATT and JOHN H. STEVENS, of Newark, in the county of Essex and State of New Jersey, have invented a new and useful Improvement in the Production of Articles by Solidifying Leather Pulp, of which the following is a specification.

The invention relates to the production of various articles by solidifying leather pulp or leather by means of heated dies.

Its distinctive novelty consists in subject ing the leather or leather pulp to pressure in molds at a definite degree of heat for a definite period of time.

Articles have heretofore been formed by pressing leather pulp or leather in molds; but in no instance has a particular degree of heat been applied for a particular period to produce an article having the distinctive and original characteristics of those which may be produced by the means hereinafter set forth.

In practice leather of any kind may be used; but we intend to utilize leather skivings and waste leather of every description rather than employ that which has a recognized commercial value.

Having cleaned the skivings or leather in. any convenient manner, the same are, by preference, immersed in a bath of water heated to a temperature of about 150 Fahrenheit, and allowed to remain, under ordinary conditions, for a period of about one hour. The object of this bath or soaking is to remove the oleaginous matter from the leather and prepare it for further treatment. While the material is in the bath the water penetrates the leather, expelling the oily matter, which rises to the surface of the water, and may be removed at pleasure.

When the bath is used, after the leather is taken out it is thoroughly dried in any suitable manner, preferably in a tumblin g-barrel, at a temperature of about 130 Fahrenheit, when it is ready to be ground. The bath or soaking is not, however, an essential step, and may be dispensed with, if preferred.

The result is much more satisfactory when the oleaginous matter is removed, and we recommend that the bath or soaking be invariably made use of. Nevertheless, in many in- (Specimens) stances a good result will be effected without employing it.

Other ways of accomplishing a removal will suggest themselves to the skilled operator.

Whatever serves to expel the oil or grease from the leather will effectuate the objects of the bath.

The grinding of the leather is effected by means of any suitable mill, in which the material is reduced to the requisite degree of fineness, according to the character of the article to be produced.

If the article is one requiring elegance of polish and finish, the material should be ground very fine. If durability is the chief desideraturn, the material may be left in a somewhat coarser state. The reduction of the material in the mill, however, is a matter of judgment, and will be readily understood by those skilled in the art to which the invention relates without further explanation.

The material, having been ground, is ready for the molds.

The foregoing preliminary steps will be carried out without difficulty, but those hereinafter described require great care on the part of the operator, and should not be hastily or indiscreetly attempted.

In the description we give of the heat and pressure and length of time they are to be applied we contemplate their employment in the treatment or fabrication of an article of a mean thickness of about half an inch. Of course articles of greater or less thickness may be produced by the means we indicate, as hereinafter set forth; but the particular degrees of heat and pressure and the length of time the article is toremain in the dies and under pressure have relation only to an article which is, when finished, about half an inch in thickness or diameter. The description as we present it, therefore, is to be regarded as an illustration or rule from which those skilled in the art may, by comparison and reflection, successfully treat articles of different thicknesses, and not as affording a guide for the indiscriminate production of articles of various thicknesses and diameters.

The molds are of any construction which will permit of their being suitably heated and their contents subjected to great pressure, as hereinafter set forth. In order to preserve a uniformity of temperature, they are, by preference, placed between steam-tables, or otherwise arranged so as to preclude their coolin g during the application of the pressure.

We prefer to heat the molds to from about 240 to 250 Fahrenheit, and to employ, when they are so heated, a pressure of not less than, say, about five thousand (5,000) pounds to the square inch.

The temperature and pressure, however, are somewhat dependent upon each other. The degree of pressure we have specified-five thousand (5,000) pounds to the square inch will, as a general rule, produce a satisfactory result when the molds are heated to a temperature above 200 Fahrenheit; and if the temperature of the molds be raised to, say,

240 or 250 Fahrenheit, or somewhathigher, a fair result may be etl'ected by a pressure considerably lower than five thousand pounds to the square inch, although not as good a result as when a pressure of about five thousand pounds or a greater pressure is made use of. V0 do not, therefore, limit ourselves to any specific degree of pressure or any specific degree of heat, as it is not possible to exactly define the limits within which the improved result may be effected.

The molds having been made ready, as hereinbefore recited, the material, prepared as above set forth, is inserted and the pressure applied, the temperature being preserved and the pressure sustained uninterruptedly for a fixed period.

It is of capital importance that the material be permitted to remain in the molds for a definite time, approximately neither more nor less. If it remains for too short an interval, it will not be successfully solidified, and if it remains too long it will be burned, and thus rendered valueless.

When the temperature of the dies is about 250 Fahrenheit and the pressure about five thousand pounds to the square inch, the material will be permitted to remain in the molds for about ten minutes. If the heat and pressure are both or either greater, this period may be somewhat varied.

\Ve do not, therefore, limit ourselves to a continuance of the pressure for any exact and specific length of time, as it will necessarily vary more or less, according to the temperature of the dies, the pressure, and other circumstances.

After remaining in the mold for the period specified the article will be removed, when it will be found to bear a striking resemblance to ebony, to have a very hard and highly-polished surface, and be in a finished condition.

In describing the temperature of the molds and the pressure and length of time the material remains in the molds, as hereinbefore mentioned, we have presented a detailed statement having relation to the treatment of an article half an inch in thickness. Where it is desired to produce an article of a thickness or diame ter greater or less than half an inch the heat, pressure, and length of time the material is permitted to remain in the molds will be varied according to the requirements of the case.

It is manifestly impossible to lay down an exact formula for each and every thickness or diameter. The illustration and description hereinbefore presented will, however, afford such a guide that there will be little difficulty in understanding and successfully practicing the invention in all cases.

The matrices will be of any configuration, the process being generally applicable to the production of small articles, such as are molded, cast, or otherwise formed in molds or dies, or by analogous means, out. of any known substance or material.

In using the terms leather and leather pulp we do not intend that the shall be understood to bear a narrow or exact technical meaning. While we prefer to use as pure a leather pulp as possible, the particles of leather may be combined with other materials, if preferred, without necessarily atfectin g the result. Thus mineral or vegetable fibers, emery, and other materials which are inert under heat may be used in combination with the leather pulp, and when such materials are employed the temperature of the molds will be raised to a degree which will cause the particles of leather to assume a liquesccnt state. This will occur under ordinary conditions where the temperature is raised to about from, say, 290 to 300 Fahrenheit.

By the term liquescent as herein employed we mean a state in which the particles of leather, while not strictly in what is commonly known as a fluid condition, are af fected to such an extent that they are of about the consistency, for example, of tar. Except that the temperature of the molds is raised to a higher degree, the process is the same where the inert material is combined with the leather as where it is not.

hat we claim as our invention, and desire to secure by Letters Patent, is-

l. The process herein described of forming articles of leather pulp, which consists in pressing the pulp for a definite period in molds heated to a definite temperature, substantially as set forth.

2. A process of forming articles from leather pulp in which the material is retained under pressure in a heated mold for a definite period.

3. A process of producing leather pulp in which the oleaginous matter is removed and the leather then desiccated and ground.

4. A process of forming articles from leather in any form in which the oleaginous matter is removed from the leather, the leather then desiccated and ground, and the pulp thus form ed subjected to the action of heated molds.

5. A process of forming articles from leather pulp and any material that is inert under heat,

perature which causes the particles of leather to become liquescent, substantially as set forth.

In testimony that We claim the foregoing improvement in the production of articles by solidifying leather pulp, as above described, we have hereunto set our hands this 4th day of August, 187 9.

in which the particles of leather are reduced to a liquescent state, substantially as set forth.

6. An article formed of leather pulp solidified by pressure for a definite period in heated dies.

5 7. An article formed of leather pulp which has been rendered liquescent and united with any material which is inert under heat.

8. A process in which leather pulp and a 10 material which is inert under heat are subjected to pressure in molds heated to a tem- JOHN W. HYATT. Witnesses: JOHN H. STEVENS.

ABRAHAM MANNERs, D. J. LEWIS. 

